The present invention relates to a beam employed as a reinforcement of a vehicle body, in an impact structure or the like, and more particularly to a structural beam comprising a hollow shape having parallel or substantially parallel deformation walls oriented perpendicularly to a direction of anticipated load impact exposure.
Such beams are employed, e.g., in car doors as protection for vehicle occupants against a side collision. Apart from the need to absorb applied impact energy, the beam should also be as light as possible in order to avoid an unnecessary increase in body weight of the vehicle. German DE 3,606,024 discloses a beam of this type that is dimensioned over its entire length to absorb the actual maximal anticipated impact load. Consequently, such beam does not comply with the need regarding an optimal strength/weight relationship.
From German DE 380 724 it is known to resolve the above problem by provision of a constructed beam where one or more additional complementary shapes are connected to a hollow shape along the actual area to be exposed to an impact load. German DE 3,826,958 discloses a constructed beam consisting of two spot welded shapes locally reinforced by means of outwardly or inwardly positioned and fastened additional shapes. Rather complicated solutions are presented in both the above cases, and the application therein of additional shapes results in extra assembly operations and increased manufacturing costs.